Hydrostatically journalled slide and slide guide

ABSTRACT

A hydrostatically journaled slide and slide guide combination having a slide member of substantially C-shaped cross section for cooperative engagement with a slide guide member having a partially T-shaped cross section when the C-shape of the slide is oriented at 90* with respect to the T-shape of the slide guide. The slide guide member is formed of a rigid baseplate and a Tshaped bed having an upright member and a cross member being supported by the baseplate. A rectangular longitudinal slot is located in the top surface of the bed and along both side surfaces. The slide member is formed with rectangular longitudinally extending bearing feet which project into and are received by each of the slots on the slide guide member. A pair of bearing chambers supplied with hydraulic fluid under pressure are arranged on oppositely located surfaces of each of the bearing feet to produce oppositely directed compressive forces on the projecting bearing feet so that the slide will be bilaterally journaled on the guide member in two separate directions which are oriented at right angles to each other, thereby preventing bending moments in the slide and slide guide combination and allowing for lightweight rigid construction.

United States Patent [72] lnventor .hcobus GljsbertCornelisDeGut Nlimegen, Netherlands [211 App]. No. 827,211 [22] Filed May 23,1969 1451 Patented June8, 1971 [73] Assignee U.S.P1!lllps-Corporatlon New York, N.Y. [32] Priority May3l, 1968 [33] Netherlands [31] 6,807,674

[54] HYDROSTATICALLY JOURNALLED SLIDE AND SLIDE GUIDE 4 Claims, 6 Drawing Figs.

[52] U.S.Cl 308/5, 90/58,184/5 [51] Int.Cl. F16cl/24, Fl6c 17/16 [50] FleldofSearch 308/5, 9, 3, 160, 122; 184/5; 90/58 [561 References Cited UNITED STATES PATENTS 3,231,319 1/1966 Porath 308/5 3,355,990 12/1967 Thum 308/5X 3,395,947 8/1968 Brown..... 308/5 3,439,581 4/1969 Wilkins 308/5X 3,442,560 5/1969 De Gast 308/5 3,466,951 9/ 1 969 Greenberg BOB/5X 3,484,064 12/1969 Koenig lll 308/3X FOREIGN PATENTS 1,149,591 5/1963 Germany 308/5 Primary Examiner-Manuel A. Antonakas Attorney-F rank R. Trifari ABSTRACT: A hydrostatically joumaled slide and slide guide combination having a slide member of substantially C-shaped cross section for cooperative engagement with a slide guide member having a partially T-shaped cross section when the C- shape of the slide is oriented at 90with respect to the T-shape of the slide guide. The slide guide member is formed of a rigid baseplate and a T-shaped bed having an upright member and a cross member being supported by the baseplate. A rectangular longitudinal slot is located in the top surface of the bed and along both side surfaces. The slide member is formed with rectangular longitudinally extending bearing feet which project into and are received by each of the slots on the slide guide member. A pair of bearing chambers supplied with hydraulic fluid under pressure are arranged on oppositely located surfaces of each of the bearing feet to produce oppositely directed compressive forces on the projecting bearing feet so that the slide will be bilaterally journaled on the guide member in two separate directions which are oriented at right angles to each other, thereby preventing bending moments in the slide and slide guide combination and allowing for lightweight rigid construction.

I'IYDRQSTATICALLY .IOUIRNALLEI) SLIDE AND SLIDE GUIDE The invention relates to a hydrostatically journaled slide and slide guide, in which the slide has a substantially C-shaped cross section the inside of which cooperates with the slide guide. The slide is bilaterallyjournaled in two directions which extend at right angles to each other. Bearing chambers are therefore provided on surfaces of the slide cooperating with the slide guide. The chambers communicate through a restriction with a supply for hydraulic medium under pressure.

In hydrostatically journaled slides, large forces occur between the slide and the slide guide, which forces are the result of the hydraulic pressure in the bearing chambers. These forces may give rise to deformation in the slide or the slide guide; the bearing surfaces of the slide and the slide guide are forced apart with great force, so that the height of the bearing gaps can become considerably larger than the desired value. In order to obtain an accurate operation of the slide, however, it is necessary the bearing gaps be maintained at the desired value. In order to obtain a sufficiently large rigidity, large and heavy constructions are used in the known embodiments.

It is the object of the invention to provide a hydrostatically journaled slide which requires only small and lightweight constructions and nevertheless has a very large rigidity and hence an extremely accurate operation. In order to achieve this, the slide guide according to the invention consists of a very rigid baseplate and a bed which has a substantially T-shaped cross section.

The bed is provided with at least one rectangular slotshaped recess, on both the two side surfaces and on the top surface. The slide comprises rectangular projecting bearing feet which fit in the recesses on the surfaces of the bed. Each of the rectangular bearing feet of the slide located on opposite surfaces are provided with bearing chambers. In this construction compressive forces of opposite directions are exerted on the projecting bearing feet of the slide, so that the slide cannot experience any deformation as a result of bending torques. In the T-shaped bed the slide guide is located in two perpendicularly arranged directions. Dependent upon the shape of the bed, the result of these forces will produce either no bending torques at all or bending torques of a low value. Thus a very rigid construction is ensured. Rigidity of this construction is not affected by lateral forces. These forces are transmitted, through the bed and the very thick hydraulic film in the bearing gaps, to the baseplate easily be given a very rigid construction. A very rigid, yet lightweight construction of the slide and slide guide can thus be achieved. As a result, there are many uses for the lightweight rigid slide and slide guide. Extremely accurate positioning of the slide is always obtained and the deviations from a straight line are extremely small.

in one embodiment of the invention, the parts of the slide guide which are situated between slot-shaped recesses, ensuring a bearing and, viewed in the cross section, are mutually directed at right angles and are of square shape. All the recesses have the same depth and the bearing chambers of bearing feet fitting in said recesses are situated at the same distance from the outside of the recesses. The advantage of this embodiment is that of bending torques on the guide is fully avoided and accurate positioning of the slide is ensured. The deviations from a straight line, when the slide is displaced over a distance of, for example, cm., are only a fraction ofa ,um.

Another embodiment provides that the slide be constructed from a number of separate elements which are united by means of connection members to form one assembly. The manufacture of this slide is very simple and accurate. This construction is possible because the forces on the slide are fully balanced.

In a further embodiment according to the invention, the bed of the slide is constructed from separate elements each having a rectangular shape and by means of connection members to form one assembly together with the baseplate. In this case,

bending torques cannot be entirely avoided, however, the resulting deformation is extremely small. This construction has the advantage that, from a point of view of manufacture, the construction can very simply be realized.

In order that the invention may be readily carried into effect, a few examples thereof will now be described in greater detail, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a cross-sectional view of a conventional construction ofa slide with slide guide,

FIG. 2 is a cross-sectional view of an embodiment of the slide with the guide according to the invention,

FIG. 3 shows the slide guide of FIG. 2,

FIG. 4 shows the slide of FIG. 2,

FIGS. 5 and 6 are cross-sectional views of further embodiments of the slide and slide guide according to the invention.

FIG. I shows a conventional bilaterally journaled slide 1 with the slide guide 2. The upper part of the slide guide 2 is T- shaped in cross section, while the slide is substantially C- shaped being rotated through with respect to the T-shaped slide guide. The slide comprises bearing chambers 38 to which hydraulic medium, for example, oil, is applied under pressure through a restriction not shown. The horizontal beam of the T thereby forms, with the slide 3, bilaterally operative hydrostatic bearings, two of which operate in a vertical direction and one operating in a horizontal direction. Due to the forces denoted by arrows which are exerted on the slide as a result of the hydraulic medium, bending torques occur in the slide which try to deform the slide. The height of the bearing gaps, which usually will have to be 30p, can be increased considerably so that the stiffness of the hydraulic medium in the bearing gaps decreases considerably and the accuracy of the position of the slide is significantly reduced. In order to prevent this decrease in accuracy, it will be necessary to make the slide 'very rigid. This means that the construction of the slide will have to be heavy and bulky.

The cross-sectional views of the FIGS. 2 to 4 show a first embodiment of a slide according to the present invention. The slide guide is formed by a rigid baseplate 10, to which a bed 12 is secured by means of tap bolts 11. The bed 12 has a substantially T-shaped cross section and it comprises one slot-shaped recess 13 (see FIG. 3) for receiving horizontal forces and two slot-shaped recesses 14 and 15 for receiving vertical forces. The slide I6, which, in the example shown is constructed from a number of interconnected components, has a substantially C-shaped cross section which is rotated through 90 with respect to the T-shae of the bed I2. The slide 16 comprises two horizontal rectangular projecting bearing feet 17 and I8 and one vertical rectangular projecting bearing foot 19. In each of the bearing feet 17 and I8, bearing chambers 20 and 21 are formed (see FIG. 4) while bearing chambers 22 and 23 are shown in bearing foot 19. The bearing chambers communicate through a reduction in area (not shown) with a supply for hydraulic medium under pressure, for example, oil. Each of the bearing feet thus serves, together with the recess in the guide, as a bilaterally operative hydrostatic bearing and can therefore receive forces in two mutually opposite directions.

FIG. 4 shows the forces which occur on the slide 16 as a result of the hydraulic medium. The bearing surfaces and the pressure of the hydraulic medium are chosen equally large for each of the bearings, so that, as can clearly be seen, the hydraulic forces are fully balanced and hence no bending torques occur in the slide.

FIG. 3 shows the play of forces on the slide guide. In this case also the hydraulic forces do not give rise to the occurrence of bending torques. The resultants K and K of the forces K, and K, and K and K respectively, are at right angles to the planes 11-0 and b-brespectively, so that only tensile forces occur in the bed I2. The resultant K of the forces K and K is at right angles to the baseplate 10 and is received by the bolts 11. The baseplate 10 can begin a very rigid construction in a simple manner, for example, by suitable material cho' ice, or by providing reinforcement ribs. The size of the bearing gaps will hence not be influenced by deformations as a result of bending torques, so that the position of the slide meets very high requirements. In addition, both the slide and the slide guide may be given a lightweight construction while they nevertheless are very rigid. Very accurate positioning of the slide will be obtained by providing that a very stiff film hydraulic medium in the bearing gap. This is easily provided for by means of a double-acting reduction in area divided in two parts by a diaphragm, as is described in US. Pat. No. 3,442,560. A vertical external load received by the slide is transferred, through the stiff hydraulic film in the bearing gap and through the bed, directly to the rigid baseplate l0, and deformation does not occur. In the case of an external horizontal load of the slide, for example, a force exerted on the slide in FIG. 2 to the left, this force will try to rotate the slide 16 and the bed 12 relative to the baseplate 10. However, this is prevented by the bearing feed projecting in the bed and the very stiff hydraulic bearing film so that the external force is transmitted to the very rigid and nondeformable base plate.

FIGS. 5 and 6 show embodiments in which the bed is constructed from components 25-27 and 283l, respectively, which are secured to the base plate 10, for example by means of bolts (not shown). These constructions are very simple from a point of view of manufacture and the essential surfaces can be easily and accurately machined. Bending torques in the bed cannot be entirely avoided, however, with this simple construction. These embodiments which can easily be manufactured become very attractive when the reduction in area divided into two parts by a diaphragm, as already mentioned in the U.S. Pat. No.. 3,442,560 is used in the supply of the hydraulic medium. When this double-acting restriction is used, the pressures in the hydraulic medium can be kept low without loss of stiffness on the hydraulic bearing film. The influence of the bending torques then becomes negligable, so that the accuracy of positioning of the slide remains particularly good.

I claim:

1. A hydrostatically journaled slide and slide guide combination comprising a slide member having a substantially C- shaped cross section and a slide guide member having a par tially T-shaped cross section, said slide member being arranged for cooperative engagement with said slide member when said C-shaped slide is oriented at 90 with respect to the T-shape of the slide guide member, said slide guide member comprising a rigid baseplate, a T-shaped bed having an upright member and a crossmember, said bed being supported on said baseplate, a rectangular shaped longitudinal slot located in the top surface of said bed and a rectangular-shaped longitudinal slot located in each of the side surfaces of said bed being formed between said crossmember and said baseplate, said slide member comprising a plurality of rectangular-shaped longitudinally extending bearing feet projecting into and being received for guiding arrangement by each of the longitudinal slots of said slide guide member, at least a pair of bearing chambers provided on oppositely located surfaces of each of said rectangular bearing feet, and means for supplying hydraulic medium under pressure through a restriction to each of said bearing chambers so as to produce oppositely directed compressive bearing forces on the projecting bearing feet of the slide, whereby said slide member will be bilaterally journaled on said slide guide member in two separate directions oriented at right angles to each other to thereby prevent occurrence of bending moments and permit rigid lightweight construction.

2. A hydrostatically journaled slide and slide guide as claimed in claim 1 wherein the parts of the slide guide which are situated between slot-shaped recesses ensuring a bearing and viewed in the cross section of the guide, are directed mutually at right angles and are of square shape, all the recesses having the same depths and the bearing chambers of bearing feet fitting in said recesses being situated at the same distance from the outside of the recesses.

3. A hydrostatically journaled slide and slide guide as claimed in claim l wherein the slide comprises a number of separate elements combined by means of connection members to form a unitary assembly.

4. A hydrostatically journaled slide and slide guide, as claimed in claim 1 wherein the bed of the slide guide member comprises separate elements which each have a rectangular shape and which are combined to form one assembly together with the baseplate by means of connection members. 

1. A hydrostatically journaled slide and slide guide combination comprising a slide member having a substantially C-shaped cross section and a slide guide member having a partially T-shaped cross section, said slide member being arranged for cooperative engagement with said slide member when said C-shaped slide is oriented at 90* with respect to the T-shape of the slide guide member, said slide guide member comprising a rigid baseplate, a T-shaped bed having an upright member and a crossmember, said bed being supported on said baseplate, a rectangular shaped longitudinal slot located in the top surface of said bed and a rectangular-shaped longitudinal slot located in each of the side surfaces of said bed being formed between said crossmember and said baseplate, said slide member comprising a plurality of rectangular-shaped longitudinally extending bearing feet projecting into and being received for guiding arrangement by each of the longitudinal slots of said slide guide member, at least a pair of bearing chambers provided on oppositely located surfaces of each of said rectangular bearing feet, and means for supplying hydraulic medium under pressure through a restriction to each of said bearing chambers so as to produce oppositely directed compressive bearing forces on the projecting bearing feet of the slide, whereby said slide member will be bilaterally journaled on said slide guide member in two separate directions oriented at right angles to each other to thereby prevent occurrence of bending moments and permit rigid lightweight construction.
 2. A hydrostatically journaled slide and slide guide as claimed in claim 1 wherein the parts of the slide guide which are situated between slot-shaped recesses ensuring a bearing and viewed in the cross section of the guide, are directed mutually at right angles and are of square shape, all the recesses having the same depths and the bearing chambers of bearing feet fitting in said recesses being situated at the same distance from the outside of the recesses.
 3. A hydrostatically journaled slide and slide guide as claimed in claim 1 wherein the slide comprises a number of separate elements combined by means of connection members to form a unitary assembly.
 4. A hydrostatically journaled slide and slide guide, as claimed in claim 1 wherein the bed of the slide guide member comprises separate elements which each have a rectangular shape and which are combined to form one assembly together with the baseplate by means of connection members. 